There is a description of how to add documents in the help section. If you're going to post documents publicly, you'll need to indicate in the Settings section (when you edit the event) that you will use the Notice Board.

You add documents by clicking on the Common Documents or Event Documents (with a plus icon in front of them) on the Event Panel page.

Common Documents are documents that are in the Document Library, but can be shared on the Event by association. Event documents are unique documents you are adding to the Event repository.

In your case Paul, you could not see the links in the application because the security was looking for a judge certification. I've fixed that so any official can add documents.